The present disclosure relates to image forming apparatuses using an electrophotographic system, such as copiers, printers, facsimile machines, and multifunction peripherals incorporating their functions. More particularly, the present disclosure relates to image forming apparatuses provided with a mechanism for protecting a photosensitive member arranged near an openable-closable member.
Conventional image forming apparatuses using an electrophotographic system, such as printers, copiers, and facsimile machines, transfer a toner image to the surface of a sheet while conveying the sheet to a photosensitive drum. Then, the toner image transferred on the surface of the sheet is fixed to the sheet by a fixing portion. The sheet to which the toner image has now been fixed is discharged to outside the image forming apparatus. A sheet conveying passage leading from the photosensitive drum to the fixing portion can be opened for jam (sheet jam) handling by opening the openable-closable member rotatably supported on an image forming apparatus main body.
Here, when the openable-closable member is opened, the surface of the photosensitive drum is exposed to outside the image forming apparatus, and the photosensitive drum is exposed to external light. As a result, a photosensitive layer formed on the surface of the photosensitive drum may be degraded. Also, if the exposed photosensitive drum is touched by a hand or an object, the surface of the photosensitive drum may be contaminated or scratched.
To avoid that, there is provided a drum cover that moves, in coordination with the openable-closable member, between a position where the drum cover covers the photosensitive drum and a position where the drum cover is retracted from the sheet conveying passage. When the openable-closable member is closed, the drum cover is retracted from the sheet conveying passage, so that a toner image on the surface of the photosensitive drum can be transferred to a sheet. Opening the openable-closable member for jam handling opens the sheet conveying passage as well as causes the drum cover to cover the surface of the photosensitive drum on the side facing away from the image forming apparatus main body to prevent the surface of the photosensitive drum from being exposed to outside the apparatus.
There is provided a cooling portion for preventing an image forming unit including the photosensitive drum and a developing device from being exposed to high temperature due to heat from the fixing device. When the drum cover for protecting the surface of the photosensitive drum is retracted, the drum cover is positioned in the air flow generated by the cooling portion.